Undersea optical communication systems may include an optical transmission path extending between shore stations separated by distances of thousands of kilometers. The optical transmission path may include an optical fiber cable coupled from one shore station to another through numerous elements, such as repeaters, branching units, etc. The optical fiber cable may include multiple optical fiber pairs for bi-directional transmission of information, e.g. on a plurality of separate wavelength channels in a wavelength division multiplexed (WDM) system. The optical fiber cable, as well as housings associated with elements connected thereto, may rest on the ocean floor.
A variety of optical cable configurations are known. FIG. 1 is a simplified cross-sectional illustration of one exemplary optical fiber cable 100. As shown, the optical fiber cable 100 may include one or more layers of insulation or armor 102. A number of individual optical fibers 104, each having its own insulation, cladding and core, may be provided within the cable. A power conductor 106 may be provided at the center of the cable for providing electrical energy to remote system elements, e.g. repeaters, etc., located along the length of the cable.
A current supplied on the cable power conductors may be provided by power feed equipment (PFE) located at a shore station. For example, the cable power conductor may be connected to a positive PFE terminal at one shore station and to a negative PFE terminal at the shore station at the opposite end of the cable. A variety of power feed equipment configurations are known.
Optical systems have also been configured as detection systems for performing ocean observing functions. Such detection systems may include an optical transmission path including an optical fiber cable and other elements, such as sensors, extending between shore stations. The sensors coupled to the cable may be powered by PFE at the shore stations through a power conductor of the cable. The sensors may be deployed for a variety of purposes, such as observing the earth-ocean-atmosphere system, predicting seismic and/or tsunami events, surveillance, etc. . . .